Method and means of treating molten metal



Patented Dec. 5, 1922.

UNITED STATES- PATENT OFFICE.

FRANK L. DRIVER, JR., OF NEWARK, NEW JERSEY, ASSIGNOR T0 DRIVER-HARRIS COMPANY, OF HARRISON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

METHOD AND MEANS OF TREATING MOLTEN METAL.

No Drawing.

means for carrying it out, and has for its object to provide a new and improved method of cleansing the metal prior to casting. It

is particularly applicable to the cleansing operation which takes place after the molten metal is poured into the ladle and is especially useful for the treating of nickel alloys containing iron.

Heretofore in making alloys containing iron, such as nickel-chromium-iron alloys, it has been customary to subject the molten alloy to a final deoxidation after it has been poured into the ladle. In usual practice, in making malleable nickel and nickel alloys in which the nickel element predominates, it is customary to use for this final deoxidation magnesium in stick form, about two ounces of magnesium to one hundred pounds of resultis attained.

metal being sufiicient to accomplish the final deoxidation. While this process as carried on with nickel and nickel-copper alloys meets with success, it is found that when the magnesium in stick form is introduced into an alloy containing a substantial amount of iron there is a very quick and noticeable reaction which takes place as soon as the magnesium is forced into the melt. The old method of introducing the magnesium is as follows: Sticks of magnesium about one and one-half inches in diameter are tied on to a long rod with a flange on the bottom. The rod is plunged down through the slag and into the metal. The magnesium reacts with the iron oxides and causes a vivid flash to take place and much of the magnesium is dissipated and 10st in this reaction, the magnesium, to a great extent, coming to the top of the bath and uniting with the oxygen of the air. One object of my invention is to prevent this reaction and loss. In carrying out my invention, in its preferred form, I use, instead of the ordinary magnesium, an alloy composed of magnesium and a large percentage of nickel, such, for instance, as 50% magnesium Application filed April 24,

1919. Serial No. 292,503.

and 501% nickel, by weight. I introduce this into the ladle in the manner in which magnesium has heretofore been introduced. and thereby the desired result is accomplished, namely, the magnesium no longer comes to the top of the bath to any such extent and therefore does not unite with the air and become lost as heretofore, but, on the contrary, performs its work beneath the surface of the molten bath uniting with the oxides thereof and cleansing the alloy. The nickel content of the nickel-magnesium alloy acts to retain 'the magnesium beneath the surface of the bath, the nickel, after the cleansing effect has taken place, forming a permanent part of the alloy making up the bath. This result, I believe, is largely due to the effect that the nickel-magnesium alloy is of such specific gravity that it remains below the surface so that the magnesium therein is prevented from rising to the surface until it has accomplished its work.

As a result of this invention, I have found that it is necessary to use only about one ounce of magnesium or two ounces of the 50-50 alloy to one hundred pounds of the bath, and that a more uniform and certain When using pure magnesium one could not be sure whether the oxides were thoroughly killed or not, since the amount of magnesium that was lost in the reaction which took place varied from time to time. The metallurgical action of the magnesium alloy is the same as before. The use of the nickel-magnesium alloy results not only in a more uniform product, but is more economical.

Similar results can be attained by the use of a fifty-fifty cobalt-magnesium alloy, it being known that nickel and cobalt have common characteristics. The proportion of nickel (or cobalt) and magnesium in the cleansing alloy can be varied considerably so long as care is taken that sufficient magnesium is introduced into the bath to produce the necessary cleansing efi'ect and that the nickel (or cobalt) content shall.- not be so high as to introduce more nickel (or cobalt) than it is desired to have in the resulting product.

The violent reaction above referred to, when pure magnesium is used, results not only in the loss of magnesium but also a loss of the metal or alloy being cleansed through the violent reaction.

The nickeLInagnesiHni alloy or cobaltmagnesium alloy is made by mixingthe proper proportions of nickel and magnesium or cobalt and magnesium, and melting the same in a furnace having a deoxidized atmosphere such as hydrogen and casting them while still in such an atmosphere. This product I believe to be a new product and constitutes an essential part of my invention.

As will be evident to those skilled in the art, my invention permits of various modifications without departing from the spirit thereof or the scope of the appended claims.

What I claim is:

1. In the process of treating molten alloys adapted to be cleansed by magnesium, the improvement which consists in alloying magnesium with a heavier metal, the magnesium being approximately fifty per cent of the resultant product, and combining the resultant product With the molten alloy.

2. The process of treating a molten bath of an alloy containing iron and a metal having the characteristics common to nickel and cobalt, which consists in introducing into said bath before pouring a cleansing alloy of magnesium and said metal having the characteristics common to nickel and cobalt.

3. The process of treating a molten bath of an alloy containing iron and a metal having the characteristics common to nickel and cobalt, which consists in introducing into said bath before pouring a cleansing alloy of magnesium and said metal having the characteristics common to nickel and cobalt, the alloy introduced containing approximately fifty per cent of magnesium.

4. An alloy for treating a molten metallic bath containing approximately fifty per cent magnesium and fifty per cent nickel.

5. A metallic alloy comprising magnesium and a metal having the characteristics common to nickel and cobalt, the magnesium constituting approximately fifty per cent of the alloy.

FRANK L. DRIVER, JR. 

